Apparatus for conveying lead frame

ABSTRACT

A lead frame conveying apparatus comprises a driving force converting unit for transmitting to a frame receiving arm a horizontal reciprocating linear motion of an elliptic motion of a timing belt placed over two timing pulleys between the centers of the timing pulleys and converting semicircular motions at both ends of the horizontal reciprocating linear motion into vertical reciprocating linear motions by employing rolling contact for absorbing the horizontal component thereof and transmitting the vertical reciprocating linear motion to the frame receiving arm so as to put the frame receiving arm into a rectangular motion. The apparatus thus requires only one induction motor as a driving device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lead frame conveying apparatus forconveying a lead frame between guide rails which are extended parallel.The present invention also includes a transverse conveying mechanismused in the lead frame conveying apparatus and a method of converting anelliptic motion performed in the transverse conveying mechanism into arectangular motion.

2. Description of the Related Art

FIG. 5 is a perspective view showing a conventional apparatus forconveying a lead frame. In the drawing, a lead frame 1 is transferredbetween two guide rails 2 and 3 by a frame receiving arm 4. For example,when the lead frame 1 is transferred from the guide rail 2 to the guiderail 3, the frame receiving arm 4 is moved in the order of A-B-C-D shownby arrows in the drawing. The guide rails 2 and 3 comprise two rails 2a,2b and 3a, 3b, respectively, which are extended parallel. A linear guidebearing 11a is slidably mounted on a liner guide rail 11 on a base block21, a bearing block 20 being fixed to the linear guide bearing 11athrough a holder 5. A shaft 6 is passed through a bearing hole (notshown) in the bearing block 20 so as to connect the frame receiving arm4 and a plate 7 and is fitted in the bearing hole so as to be axiallyslidable. The shaft 6 is provided at either side of the linear guiderail 11. The plate 7 has a lower end member 8 which is downwardlyextended and on which a rolling bearing 9 is provided. An extension coilspring 10 interposed between the bearing block 20 and the plate 7produces the force to upwardly move a portion comprising the framereceiving arm 4, the shafts 6, the plate 7, the member 8 and the rollingbearing 9. A guide plate 13 is attached to two linear guide bearings12a, 12b which are vertically slidable and which are provided on thebase block 21 so that the guide plate 13 contacts with the rollingbearing 9 which is upwardly moved by the coil spring 10. Extension coilsprings 10a, 10b are respectively provided between the guide plate 13and the base block 21 at both ends of the guide plate 13 so as toconstantly generate the force to upwardly move the guide plate 12 (thecoil spring 10a is not shown in FIG. 5). A rolling bearing 13a inrolling contact with a vertically moving cam 14 is provided at thecenter on the side of the guide plate 13, which is opposite to the sidethereof engaged with the linear guide bearings 12a, 12b. The verticallymoving cam 14 is eccentrically provided on the rotational shaft of amotor 16. A timing belt 18 placed over timing pulleys 19a , 19b isdriven by a pulse motor 17. The connecting member 20a provided on thebearing block 20 holds the timing belt 8 therein so as to connect thebearing block 20 and the timing belt 18. The base block 21 is fixed to abase plate 22. FIG. 6 is a side view showing the basic operation of theframe receiving arm 4 of the conventional frame conveying apparatus inthe case where the lead frame 1 is transferred from the guide rail 2 tothe guide rail 3. When the lead frame 1 is conveyed to the guide rail 2by an external apparatus (not shown), the frame receiving arm 4positioned below the guide rail 2 is upwardly moved for scooping up thelead frame 1. The frame receiving arm 4 is transversely moved from aposition above the guide rail 2 to a position above the guide rail 3while holding the lead frame 1. The frame receiving arm 4 is downwardlymoved for placing the lead frame 1 on the guide rail 3. The framereceiving arm 4 is then transversely moved from a position below theguide rail 3 to a position below the guide rail 2. The frame receivingarm 4 performs such a one-cycle motion. Each of the guide rails 2 and 3is partially cut off to form a space which allows the frame receivingarm 4 to scoop up the lead frame 1 on the guide rail and place the leadframe on the guide rail, as shown in FIG. 5.

The operation of the conventional apparatus for conveying a lead frameis described below with reference to FIGS. 5 and 6. The frame receivingarm 4 waits for the lead frame 1 at point A. When the lead frame 1 isfed to the guide rail 2, the motor 16 is driven, and the verticallymoving cam 14 eccentrically provided on the rotational shaft of themotor 16 is thus rotated. The rolling bearing 13a provided on the guideplate 13 is vertically moved while making rolling contact with theperiphery of the vertically moving cam 14 by virtue of the coil springs10, 10a, 10b in accordance with the distance between the portion ofcontact with the periphery of the vertically moving cam 14 and therotational shaft. This causes the whole guide plate 13 to be verticallymoved. When the motor is driven, and when the guide plate 13 is upwardlymoved according to the rotation of the vertically moving cam 14, aportion comprising the rolling bearing 9, the lower end member 8 and theplate 7 is upwardly moved. The frame receiving arm 4 connected to theplate 7 by the shaft 6 is thus upwardly moved to point B so as to scoopup the lead frame 1 from the guide rail 2. The motor 16 is stopped athalf rotation. A predetermined number of pulses are then applied to thepulse motor 17 from an external pulse generator (pulse motor driver)according to the distance between the guide rails 2 and 3 so that thepulse motor 17 is driven. When the timing pulleys 19a, 19b are rotatedby driving the pulse motor 17, the timing belt 18 is rotated followingthe rotation of the pulleys 19a, 19b. The rotation of the timing belt 18is converted into a transverse horizontal linear motion of the bearingblock 20 through the connecting member 20a. The portion comprising theframe receiving arm 4, the bearing block 20, the connecting member 20a,the shaft 6, the plate 7, the lower end member 8 and the rolling bearing9 is thus horizontally moved from point B to point C in the transversedirection. When the motor 16 for driving the vertically moving cam 14 isthen half rotated, the guide plate 13 is downwardly pushed by thevertically moving cam 14, and at the same time, the rolling bearing 9 isalso dowwnwardly pushed. The frame receiving arm 14 is consequentlydownwardly moved to point D so as to place the lead frame 1 on the guiderail 3. When the pulse motor 17 is driven to rotate in the reversedirection, the frame receiving arm 4 is returned to point A to completeone cycle.

In the conventional apparatus for conveying a lead frame configured asdescribed above, since the frame receiving arm must be horizontallypositioned with high accuracy according to the positions of the guiderails, the pulse motor is used. However, the pulse motor driver isrequired as an external apparatus for driving the pulse motor. Theconventional apparatus thus has the problem that the need for two motorsfor vertical and horizontal motion increases the cost of the apparatus.

SUMMARY OF THE INVENTION

The present invention has been achieved for solving the above problem,and it is an object of the present invention to provide an apparatus forconveying a lead frame which comprises a single motor used forperforming a sequence of operations (referred to as "rectangular motion"hereinafter) comprising vertical operations and horizontal operationsand describing a rectangle.

It is another object of the present invention to provide a transverseconveying unit used in the lead frame conveying apparatus and a methodof converting an elliptic motion into a rectangular motion.

In order to achieve the objects, the present invention provides a leadframe conveying apparatus for transferring a lead frame sent to one oftwo guide rails between the two guide rails by scooping up the leadframe in a space formed by partially cutting off each of the guiderails, the apparatus comprising frame receiving means for carrying thelead frame, moving block means holding said frame receiving means sothat the frame receiving means vertically slides so as to be elasticallybalanced at a predetermined neutral position thereof in the horizontaldirection along the transfer direction, horizontal linear guide meansextended between the two guide rails in order to horizontally guide themoving block means along the transfer direction of the lead frame,stopper means for horizontally positioning the frame receiving meanscorresponding to the positions of the two guide rails, driving forcetransmitting means for making an elliptic motion which describes anellipse and which comprises a horizontal reciprocating linear motionbetween the two guide rails and semi-circular motions at both ends ofthe reciprocating motion, driving means for giving a driving force tothe driving force transmitting means, driving force converting meanswhich is provided on the moving block means and which is connected tothe driving force transmitting means and the frame receiving means so asto transmit the horizontal reciprocating linear motion in the ellipticmotion of the driving force transmitting means to the frame receivingmeans and convert the semi-circular motions at both ends of thereciprocating linear motion into vertical reciprocating linear motionsby employing rolling contact for absorbing the horizontal componentthereof and transmit the vertical reciprocating linear motions to theframe receiving means so that the frame receiving means performs arectangular motion.

The present invention further includes a transverse conveying mechanismused in the lead frame conveying apparatus and a method of converting anelliptic motion into a rectangular motion.

In the present invention, the elliptic motion of the driving forcetransmitting means driven by single driving means is converted into therectangular motion which describes a rectangle by the driving forceconverting means which employs rolling contact, and transmitted to theframe receiving means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view showing a lead frame conveyingapparatus according to an embodiment of the present invention;

FIG. 2 is a top view of the lead frame conveying apparatus shown in FIG.1;

FIG. 3 is a front view of the lead frame conveying apparatus shown inFIG. 1 without showing a timing pulley portion;

FIG. 4 is a partially sectional side view of a principal portion of thelead frame conveying apparatus shown in FIG. 1;

FIG. 5 is a schematic perspective view of a conventional lead frameconveying apparatus; and

FIG. 6 is a drawing for explaining the operation of the lead frameconveying apparatus shown in FIG. 5.

DESCRIPTION OF PREFERRED EMBODIMENTS

An embodiment of the present invention is described below with referenceto the drawings. FIG. 1 is a schematic perspective view of a lead frameconveying apparatus in accordance with an embodiment of the presentinvention, FIG. 2 is a partially sectional top view, FIG. 3 is a frontview without showing a timing pulley portion, and FIG. 4 is a partiallysectional side view of a principal portion. In each of the drawings, theportions which are the same as or correspond to those of theconventional apparatus shown in FIGS. 5 and 6 are denoted by the samereference numerals. The arrangement of a lead frame conveying apparatusaccording to the present invention is outlined below. The ellipticmotion of timing pulleys 19a, 19b and a timing belt 18 placed over thepulleys 19a, 19b, which serve as driving force transmitting means, isconverted into a rectangular motion, which comprises vertical motionsand horizontal motions so as to described a rectangle, by a moving block100 serving as moving block means and the driving force converting meansdescribed below which is loaded on the moving block 100. The rectangularmotion is then transmitted to a frame receiving arm 4 serving as framereceiving means.

In the perspective view of FIG. 1, a base plate 22 is a base on whichthe lead frame conveying apparatus is installed. A horizontal linearguide rail 11 fixed on the base plate 22 so as to serve as horizontallinear guide means horizontally guides the moving block 100. Aninduction motor 17 serving as driving means rotates the timing pulley19b through gears 15a, 15b so that the timing belt 18 placed over thetiming pulleys 19a, 19b performs an elliptic motion. The elliptic motionof the timing belt 18 comprises the horizontal reciprocating rectilinearmotion within the distance between the centers of the timing pulleys19a, 19b and the semi-circular motions at both ends of the reciprocatingrectilinear motion, i.e., outside the distance between the centers ofthe timing pulleys 19a, 19b. Stoppers 25a, 25b serving as stopper meanshorizontally position the frame receiving arm 4 according to thepositions of the guide rails 2, 3 and abut, at predetermined positionsat both ends of the horizontal motion, against the slide block 23 of themoving block 100 to which the lower end member 4a of the arm 4 isattached so as to stop the slide block 23. The slide block 23 isslidably provided on two parallel shafts 30 supported by the bearingblock 24. A first eccentric shaft 26a provided on the side of a firstdisc 26 opposite to the moving block 100 is fixed at a predeterminedposition of the timing belt 18, the first disc 26 being rotatablyprovided on the moving block 100. The horizontal motion of the ellipticmotion of the timing belt 18 between the centers of the timing pulleys19a, 19b is transmitted through the first disc 26 to the whole movingblock 100 to which the frame receiving arm 4 is attached so that themoving block 100 is moved on the linear guide rail 11. Thesemi-circulation motion at each of the timing pulleys 19a, 19 b isconverted into a vertical motion and then transmitted to the framereceiving arm 4 through the first disc 26, the rotation shaft 35 of thefirst disc 26 which is extended through the moving block 100 (refer toFIG. 4), a second disc 28 provided at the opposite end of the rotationalshaft 35, the second eccentric shaft 28a of the second disc 28 and therolling bearing 9 fitted to the second eccentric shaft 28a.

In FIGS. 2 to 4, FIGS. 2 and 4 are partially sectional views showing theperipheral portion of the timing pulley 19a and the portion includingthe rotational shafts and bearings, respectively. FIG. 3 does not showthe portion corresponding to the timing pulleys. As shown in FIGS. 3 and4, the slide block 23 is slidably provided on the two shafts 30 throughrolling bearings 31. The two shafts 30 are supported at both endsthereof by the bearing block 24. As shown in FIGS. 2 and 4, extensionspring coils 27a, 27b are respectively interposed between the side block23 and the both sides of the bearing block 24. If no external force isapplied to the slide block 23, the slide block 23 is placed at theneutral position (generally at the center of the block 24) between theforces of the coil springs 27a, 27b. For example, when the slide block23 abuts the stopper 25a or 25b at one end of the horizontal motionthereof and is subjected to a force, the slide block 23 is slid alongthe shafts 30 against the force of the coil spring 27a or 27b andreturned to the neutral position as external force is decreased. Thevertical linear guide rail 12 vertically extended and provided on thelower end member 4a of the frame receiving arm 4 is slidably fitted tothe vertical linear guide bearing 12a provided on the slide block 23through a holder 5a. Supporting portions 19c and 19d support the timingpulleys 19a and 19b, respectively. Supporting portions 25c and 25dsupport the stoppers 25a and 25b, respectively.

As shown in FIG. 4, the moving block 100 serving as moving block meansbasically comprises the bearings block 24 which supports the slide block23 and which is fixed through the holder 5 on the linear guide bearing11a slidably fitted to the linear guide rail 11. The driving forceconverting means comprising the rotational shaft, 35, the bearing 29thereof and so on and the frame receiving means comprising the framereceiving arm 4 and so on are mounted on the moving block 100. The framereceiving arm 4 has a bottom portion (lower surface) 4b which is formedin the lower portion thereof and which has a horizontal surface inrolling contact with the rolling bearing 9 provided on the secondeccentric shaft 28a of the second disc 28. The rolling contact betweenthe bottom portion 4b and the rolling bearing 9 absorbs the horizontalcomponent of the semi-circular motion at each of the timing pulleys 19a,19b so that the vertical component only is transmitted to the framereceiving arm 4. The semi-circular motion at each of the timing pulleys19a, 19b is thus converted into the vertical motion and transmitted tothe arm 4. Assuming that the distance between the centers of therotational shaft 35 and the second eccentric shaft 28a is R, the widthof the bottom portion 4b in the direction of rolling of the rollingbearing 9 must be thus at least 2R. The driving force converting meanscomprises that first disc 26, the first eccentric shaft 26a, therotational shaft 35, the bearing 29, the second disc 28, the secondeccentric shaft 28a and the rolling bearing 9. A connecting pin 20connects the timing belt 18 and the first eccentric shaft 26a. Themounting portion 26b of the first eccentric shaft 26a has a planeportion 26c formed for mounting the connecting pin 20. The connectingpin 20 is passed through the timing belt 18 and buried at the tipthereof in the mounting portion 26b so as to be fixed to the firsteccentric shaft 26a, with the timing belt 18 held between the pin 20 andthe mounting portion 26b. Each of the timing pulleys 19a, 19b has aclearance groove 19e for the connecting pin 20 formed along the centralportion of the periphery thereof.

The operation of the apparatus is described below. The frame receivingarm 4 is waits for the lead frame 1 at point A. In this state, the slideblock 23 abuts against the stopper 25a, and the frame receiving arm 4 isplaced at a lower position. When the motor 17 is driven, the timing belt18 is rotated through the gears 15a, 15b and the timing pulley 19b tomake an elliptic motion. Since the first eccentric shaft 26a attached tothe timing belt 18 by the connecting pin 20 is thus upwardly moved alongthe outer periphery of the timing pulley 19a so as to described asemi-circle, the first disc 26 is rotated. The rotation of the firstdisc 26 causes the second eccentric shaft 28a to be rotated around thecenter of the rotatioal shaft 35 along a circle with a radius of R.Since the rolling bearing 9 is in rolling contact with the lower surface4b of the frame receiving arm 4, the rotation with a radius of R isconverted into an upward movement and transmitted to the frame receivingarm 4. The frame receiving arm 4 is thus upwardly moved to point B whilebeing guided by the linear guide rail 12 fixed to the slide block 23 soas to scoop up the lead frame 1 conveyed from an external apparatus (notshown) to the guide rail 2 comprising two rails 2a, 2b. When the motor17 is further continuously driven, the timing belt 18 continues anelliptic motion, and the first eccentric shaft 26a makes a horizontalmotion along the upper portion of the timing belt 18. At this time, theslide block 23 to which the frame receiving arm 4 is attached is at theneutral position in the bearing block 24 by virtue of the two extensioncoil springs 27a, 27b interposed between the slide block 23 and thebearing block 24. The moving block 100 comprising the bearing 29, thearm 4 and the like is moved from point B to point C by the horizontalmovement of the first eccentric shaft 26a while being guided the linearguide rail 11. When the moving block 100 reaches point C, the slideblock 23 abuts against the stopper 25b so that the frame receiving arm 4is positioned between the rails 3a, 3b of the guide rail 3. When thetiming belt 18 is further rotated, the portion of the moving block 100except the slide block 23 and the frame receiving arm 4 continues ahorizontal movement. After the first eccentric shaft 26a is passedthrough an upper contact point on the outer periphery of the timingpulley 19b, the first eccentric shaft 26a performs a downwardsemicircular motion along the outer periphery of the timing pulley 19b.The semi-circular motion of the first eccentric shaft 26a is convertedinto a downward rectilinear motion through the rotational shaft 35, thesecond disc 28, the second eccentric shaft 28a and the rolling bearing 9and transmitted to the frame receiving arm 4. The arm 4 thus lowers thelead frame 1 to the guide rail 3 and reaches point D. When the timingbelt 18 is further rotated, the first eccentric shaft 26a performs ahorizontal motion after being passed through a lower contact point onthe outer periphery of the timing pulley 19b so that the moving block100 including the frame receiving arm 4 starts to horizontally move. Atthis time, if the slide block 23 is separated from the stopper 25b, theslide block 23 is moved to a position (generally at the center of thebearing block 24) where the spring forces of the two coil springs 27a,27b are balanced. The moving block 100 then continues the horizontalmovement. When the slide block 23 abuts against the stopper 25a andreaches point A, a sequence of operations are completed in one cycle.Thus the lead frame 1 is completely transferred from the guide rail 2 tothe guide rail 3.

When the lead frame 1 is transferred from the guide rail 3 to the guiderail 2, the motor 17 is reversed so that the timing belt 18 makes anelliptic motion in the reverse direction.

As described above, in the present invention, the timing belt placedover the two timing pulleys makes an elliptic motion in which thehorizontal reciprocating rectilinear motion between the centers of thetiming pulleys, or between the stoppers provided at both ends of theconveyance direction, is transmitted to the frame receiving arm as itwas, and the remaining rectilinear motion and subsequent semi-circularmotion along each of the pulleys at both ends of the reciprocatingrectilinear motion outside of the distance between the centers of thetiming pulleys, or outside the stoppers at both ends of the conveyancedirection, is converted into a vertical reciprocating rectilinear motionby employing rolling contact and slidably attaching the frame receivingarm to the moving block with horizontal elasticity so as to absorb thehorizontal component thereof and then transmitted to the frame receivingarm. The invention thus requires only one induction motor as drivingmeans and has the effect of obtaining a method of converting an ellipticmotion to a rectangular motion at very low cost, a horizontal conveyingmechanism which employs the method, and a lead frame conveying apparatuswhich employs the conveying mechanism.

What is claimed is:
 1. A lead frame conveying apparatus for transferringa lead frame sent to one of two guide rails between said two guide railsby scooping up said lead frame in a space formed by partially cuttingoff each of said guide rails, said apparatus comprising:frame receivingmeans for carrying said lead frame placed thereon; moving block meansholding said frame receiving means so that said frame receiving meansvertically slides so as to be elastically balanced at a predeterminedneutral position thereof in the horizontal direction along the directionof transfer; horizontal linear guide means extended between said guiderails so as to horizontally guide said moving block means along saiddirection of transfer of said lead frame; stopper means for horizontallypositioning said frame receiving means according to the positions ofsaid two guide rails; driving force transmitting means which performs anelliptic motion describing an ellipse and comprising horizontalreciprocating rectilinear motion between said two guide rails andsemi-circular motions at both ends of said reciprocating rectilinearmotion; driving means for giving a driving force to said driving forcetransmitting means; and driving force converting means provided on saidmoving block means and connected to said driving force transmittingmeans and said frame receiving means so as to transmit said horizontalreciprocating rectilinear motion of said elliptic motion of said drivingforce transmitting means to said frame receiving means and convert saidsemi-circular motions at both ends of said reciprocating rectilinearmotion into vertical reciprocating rectilinear motions by employingrolling contact for absorbing the horizontal component thereof andtransmit said vertical reciprocating rectilinear motions to said framereceiving means so as to put said frame receiving means into rectangularmotion.
 2. A lead frame conveying apparatus according to claim 1,wherein:said frame receiving means comprises at least one framereceiving arm for scooping up said lead frame and carrying it placedthereon, a lower end member provided integrally with said framereceiving arm and vertically extended for supporting said framereceiving arm, and a lower surface provided at the lower end of saidlower end member and horizontally extended along said direction oftransfer; said horizontal linear guide means comprises a linear guiderail extended between said two guide rails, and a linear guide bearingmoved on said linear guide rail; said moving block means comprises aslide block for supporting said lower end member of said frame receivingmeans so that said frame receiving means can be vertically slid, atleast one shaft for elastically slidably supporting said slide block sothat said slide block is balanced at the predetermined neutral positionin the horizontal direction along said direction of transfer of saidframe, and a moving block provided with elastic materials and a bearingblock for supporting said shaft and said elastic materials and fixed tosaid linear guide bearing so as to be moved on said linear guide railalong it; said stopper means comprises stoppers provided at both ends ofsaid linear guide rail and abutting against said slide block on saidmoving block so as to position said frame receiving means with respectto said two guide rails; said driving force transmitting means comprisesa timing belt which performs an elliptic motion describing an ellipseand which is extended between said two guide rails along said linearguide rail on the side opposite to said lower end member of said framereceiving means, and two timing pulleys provided at both ends of saidtiming belt; said driving means comprises a motor for rotating one ofsaid two timing pulleys; and said driving force converting meanscomprises a rotational shaft passed through said moving block in thedirection vertical to said linear guide rail and rotatably supported, afirst eccentric shaft having one end eccentrically fixed to saidrotational shaft on the side of said timing belt and other end fixed tosaid timing belt, and a second eccentric shaft having one endeccentrically fixed to said rotational shaft on the side of said lowerend member and other end being in rolling contact with the lower surfaceof said lower end member.
 3. A lead frame conveying apparatus accordingto claim 2, wherein said other end of said first eccentric shaft isfixed to said timing belt by a connecting pin passed through said timingbelt, and said other end of said second eccentric shaft has a rollingbearing which absorbs the horizontal movement by employing rollingcontact with said lower surface of said lower end member of said framereceiving means.
 4. A lead frame conveying apparatus according to claim2, wherein said lower end member of said frame receiving means isprovided with a vertical linear guide rail vertically extended, saidslide block is provided with a vertical linear guide bearing which ismoved along said vertical linear guide rail, and said lower end memberis fitted to said slide block so as to be vertically slidable.
 5. A leadframe conveying apparatus according to claim 2, wherein said movingblock of said moving block means has two shafts which are supported bysaid bearing block and which are extended parallel along said directionof transfer of said frame, said slide block having two slide bearingsthrough which said two shafts are passed so that said slide block isslidably supported by said bearing block, and said two elastic materialsconnected between said slide block and said bearing block and pullingsaid slide block from both sides thereof so as to elastically supportsaid slide block to be balanced at the predetermined neutral position.6. A horizontal conveying mechanism performing a rectangular motion forconverting an elliptic motion of a timing belt placed over two timingpulleys into a rectangular motion and transmitting said rectangularmotion to a portion to be driven, said elliptic motion describing anellipse and comprising a horizontal reciprocating linear motion along alength not less than that of the horizontal conveying distance, andsemi-circular motions at both ends of said reciprocating linear motion,said mechanism comprising:moving block means holding said portion to bedriven so that said portion to be driven horizontally slides so as to beelastically balanced at a predetermined neutral position thereof in thehorizontal direction; horizontal linear guide means horizontally guidingsaid moving block means and having a length which is not less than thatof the horizontal conveying distance; stopper means for horizontallypositioning said portion to be driven according to the positions at bothends of said horizontal conveying distance; and driving force convertingmeans provided on said moving block means and connected to said timingbelt and said portion to be driven so as to transmit said horizontalreciprocating linear motion of said elliptic motion of said timing beltto said portion to be driven, and convert said semi-circular motions atboth ends of said reciprocating linear motion into a verticalreciprocating linear motion by employing rolling contact for absorbingthe horizontal component and transmit said vertical reciprocating linearmotion to said portion to be driven.